5f810ea66777d02e043914f9ab5a86ba7e35ef3a
[dragonfly.git] / sbin / dhclient / dhclient.c
1 /*      $OpenBSD: src/sbin/dhclient/dhclient.c,v 1.126 2009/05/20 20:37:43 thib Exp $   */
2
3 /*
4  * Copyright 2004 Henning Brauer <henning@openbsd.org>
5  * Copyright (c) 1995, 1996, 1997, 1998, 1999
6  * The Internet Software Consortium.    All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of The Internet Software Consortium nor the names
18  *    of its contributors may be used to endorse or promote products derived
19  *    from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
22  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
23  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
26  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
29  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
30  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  * This software has been written for the Internet Software Consortium
36  * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
37  * Enterprises.  To learn more about the Internet Software Consortium,
38  * see ``http://www.vix.com/isc''.  To learn more about Vixie
39  * Enterprises, see ``http://www.vix.com''.
40  *
41  * This client was substantially modified and enhanced by Elliot Poger
42  * for use on Linux while he was working on the MosquitoNet project at
43  * Stanford.
44  *
45  * The current version owes much to Elliot's Linux enhancements, but
46  * was substantially reorganized and partially rewritten by Ted Lemon
47  * so as to use the same networking framework that the Internet Software
48  * Consortium DHCP server uses.   Much system-specific configuration code
49  * was moved into a shell script so that as support for more operating
50  * systems is added, it will not be necessary to port and maintain
51  * system-specific configuration code to these operating systems - instead,
52  * the shell script can invoke the native tools to accomplish the same
53  * purpose.
54  */
55
56 #include <ctype.h>
57 #include <poll.h>
58 #include <pwd.h>
59 #include <unistd.h>
60
61 #include "dhcpd.h"
62 #include "privsep.h"
63
64 #define CLIENT_PATH             "PATH=/usr/bin:/usr/sbin:/bin:/sbin"
65 #define DEFAULT_LEASE_TIME      43200   /* 12 hours... */
66 #define TIME_MAX                2147483647
67 #define POLL_FAILURES           10
68 #define POLL_FAILURE_WAIT       1       /* Back off multiplier (seconds) */
69
70 time_t cur_time;
71
72 char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
73 char *path_dhclient_db = NULL;
74
75 int log_perror = 1;
76 int privfd;
77 int nullfd = -1;
78 int no_daemon;
79 int unknown_ok = 1;
80 int routefd = -1;
81
82 struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
83 struct in_addr inaddr_any;
84 struct sockaddr_in sockaddr_broadcast;
85
86 struct interface_info *ifi;
87 struct client_state *client;
88 struct client_config *config;
89
90 int              findproto(char *, int);
91 struct sockaddr *get_ifa(char *, int);
92 void             usage(void);
93 int              check_option(struct client_lease *l, int option);
94 int              ipv4addrs(char * buf);
95 int              res_hnok(const char *dn);
96 char            *option_as_string(unsigned int code, unsigned char *data, int len);
97 int              fork_privchld(int, int);
98
99 #define ROUNDUP(a) \
100             ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
101 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
102
103 time_t  scripttime;
104 static FILE *leaseFile;
105
106 int
107 findproto(char *cp, int n)
108 {
109         struct sockaddr *sa;
110         int i;
111
112         if (n == 0)
113                 return -1;
114         for (i = 1; i; i <<= 1) {
115                 if (i & n) {
116                         sa = (struct sockaddr *)cp;
117                         switch (i) {
118                         case RTA_IFA:
119                         case RTA_DST:
120                         case RTA_GATEWAY:
121                         case RTA_NETMASK:
122                                 if (sa->sa_family == AF_INET)
123                                         return AF_INET;
124                                 if (sa->sa_family == AF_INET6)
125                                         return AF_INET6;
126                                 break;
127                         case RTA_IFP:
128                                 break;
129                         }
130                         ADVANCE(cp, sa);
131                 }
132         }
133         return (-1);
134 }
135
136 struct sockaddr *
137 get_ifa(char *cp, int n)
138 {
139         struct sockaddr *sa;
140         int i;
141
142         if (n == 0)
143                 return (NULL);
144         for (i = 1; i; i <<= 1)
145                 if (i & n) {
146                         sa = (struct sockaddr *)cp;
147                         if (i == RTA_IFA)
148                                 return (sa);
149                         ADVANCE(cp, sa);
150                 }
151
152         return (NULL);
153 }
154 struct iaddr defaddr = { .len = 4 }; /* NULL is for silence warnings */
155
156 /* ARGSUSED */
157 void
158 routehandler(void)
159 {
160         int linkstat;
161         char msg[2048];
162         struct rt_msghdr *rtm;
163         struct if_msghdr *ifm;
164         struct ifa_msghdr *ifam;
165         struct if_announcemsghdr *ifan;
166         struct client_lease *l;
167         time_t t = time(NULL);
168         struct sockaddr *sa;
169         struct iaddr a;
170         ssize_t n;
171
172         do {
173                 n = read(routefd, &msg, sizeof(msg));
174         } while (n == -1 && errno == EINTR);
175
176         rtm = (struct rt_msghdr *)msg;
177         if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen ||
178             rtm->rtm_version != RTM_VERSION)
179                 return;
180
181         switch (rtm->rtm_type) {
182         case RTM_NEWADDR:
183                 ifam = (struct ifa_msghdr *)rtm;
184                 if (ifam->ifam_index != ifi->index)
185                         break;
186                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
187                         break;
188                 sa = get_ifa((char *)(ifam + 1), ifam->ifam_addrs);
189                 if (sa == NULL)
190                         goto die;
191
192                 if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf))
193                         error("king bula sez: len mismatch");
194                 memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len);
195                 if (addr_eq(a, defaddr))
196                         break;
197
198                 for (l = client->active; l != NULL; l = l->next)
199                         if (addr_eq(a, l->address))
200                                 break;
201
202                 if (l != NULL || (client->alias &&
203                     addr_eq(a, client->alias->address)))
204                         /* new addr is the one we set */
205                         break;
206
207                 goto die;
208         case RTM_DELADDR:
209                 ifam = (struct ifa_msghdr *)rtm;
210                 if (ifam->ifam_index != ifi->index)
211                         break;
212                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
213                         break;
214                 if (scripttime == 0 || t < scripttime + 10)
215                         break;
216                 goto die;
217         case RTM_IFINFO:
218                 ifm = (struct if_msghdr *)rtm;
219                 if (ifm->ifm_index != ifi->index)
220                         break;
221                 if ((rtm->rtm_flags & RTF_UP) == 0)
222                         goto die;
223
224                 linkstat =
225                     LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0;
226                 if (linkstat != ifi->linkstat) {
227                         debug("link state %s -> %s",
228                             ifi->linkstat ? "up" : "down",
229                             linkstat ? "up" : "down");
230                         ifi->linkstat = interface_link_status(ifi->name);
231                         if (ifi->linkstat) {
232                                 client->state = S_INIT;
233                                 state_reboot();
234                         }
235                 }
236                 break;
237         case RTM_IFANNOUNCE:
238                 ifan = (struct if_announcemsghdr *)rtm;
239                 if (ifan->ifan_what == IFAN_DEPARTURE &&
240                     ifan->ifan_index == ifi->index)
241                         goto die;
242                 break;
243         default:
244                 break;
245         }
246         return;
247
248 die:
249         script_init("FAIL", NULL);
250         if (client->alias)
251                 script_write_params("alias_", client->alias);
252         script_go();
253         exit(1);
254 }
255
256 int
257 main(int argc, char *argv[])
258 {
259         int      ch, fd, quiet = 0, i = 0, pipe_fd[2];
260         struct passwd *pw;
261
262         /* Initially, log errors to stderr as well as to syslogd. */
263         openlog(getprogname(), LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
264         setlogmask(LOG_UPTO(LOG_INFO));
265
266         while ((ch = getopt(argc, argv, "c:dl:qu")) != -1)
267                 switch (ch) {
268                 case 'c':
269                         path_dhclient_conf = optarg;
270                         break;
271                 case 'd':
272                         no_daemon = 1;
273                         break;
274                 case 'l':
275                         path_dhclient_db = optarg;
276                         break;
277                 case 'q':
278                         quiet = 1;
279                         break;
280                 case 'u':
281                         unknown_ok = 0;
282                         break;
283                 default:
284                         usage();
285                 }
286
287         argc -= optind;
288         argv += optind;
289
290         if (argc != 1)
291                 usage();
292
293         ifi = calloc(1, sizeof(*ifi));
294         if (ifi == NULL)
295                 error("ifi calloc");
296         client = calloc(1, sizeof(*client));
297         if (client == NULL)
298                 error("client calloc");
299         config = calloc(1, sizeof(*config));
300         if (config == NULL)
301                 error("config calloc");
302
303         if (strlcpy(ifi->name, argv[0], IFNAMSIZ) >= IFNAMSIZ)
304                 error("Interface name too long");
305         if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s",
306             _PATH_DHCLIENT_DB, ifi->name) == -1)
307                 error("asprintf");
308
309         if (quiet)
310                 log_perror = 0;
311
312         tzset();
313         time(&cur_time);
314
315         memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
316         sockaddr_broadcast.sin_family = AF_INET;
317         sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
318         sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
319         sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
320         inaddr_any.s_addr = INADDR_ANY;
321
322         read_client_conf();
323
324         if (interface_status(ifi->name) == 0) {
325                 interface_link_forceup(ifi->name);
326                 /* Give it up to 4 seconds of silent grace to find link */
327                 i = -4;
328         } else
329                 i = 0;
330
331         while (!(ifi->linkstat = interface_link_status(ifi->name))) {
332                 if (i == 0)
333                         fprintf(stderr, "%s: no link ...", ifi->name);
334                 else if (i > 0)
335                         fprintf(stderr, ".");
336                 fflush(stderr);
337                 if (++i > config->link_timeout) {
338                         fprintf(stderr, " sleeping\n");
339                         goto dispatch;
340                 }
341                 sleep(1);
342         }
343         if (i > 0)
344                 fprintf(stderr, " got link\n");
345
346  dispatch:
347         if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
348                 error("cannot open %s: %m", _PATH_DEVNULL);
349
350         if ((pw = getpwnam("_dhcp")) == NULL)
351                 error("no such user: _dhcp");
352
353         if (pipe(pipe_fd) == -1)
354                 error("pipe");
355
356         fork_privchld(pipe_fd[0], pipe_fd[1]);
357
358         close(pipe_fd[0]);
359         privfd = pipe_fd[1];
360
361         if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1)
362                 error("can't open and lock %s: %m", path_dhclient_db);
363         read_client_leases();
364         if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL)
365                 error("can't open %s: %m", path_dhclient_db);
366         rewrite_client_leases();
367         close(fd);
368
369         priv_script_init("PREINIT", NULL);
370         if (client->alias)
371                 priv_script_write_params("alias_", client->alias);
372         priv_script_go();
373
374         if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1)
375                 error("socket(PF_ROUTE, SOCK_RAW): %m");
376
377         /* set up the interface */
378         discover_interface();
379
380         if (chroot(_PATH_VAREMPTY) == -1)
381                 error("chroot");
382         if (chdir("/") == -1)
383                 error("chdir(\"/\")");
384
385         if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
386                 error("setresgid");
387         if (setgroups(1, &pw->pw_gid) == -1)
388                 error("setgroups");
389         if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
390                 error("setresuid");
391
392         endpwent();
393
394         setproctitle("%s", ifi->name);
395
396         if (ifi->linkstat) {
397                 client->state = S_INIT;
398                 state_reboot();
399         } else
400                 go_daemon();
401
402         dispatch();
403
404         /* not reached */
405         return (0);
406 }
407
408 void
409 usage(void)
410 {
411         fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n",
412             getprogname());
413         exit(1);
414 }
415
416 /*
417  * Individual States:
418  *
419  * Each routine is called from the dhclient_state_machine() in one of
420  * these conditions:
421  * -> entering INIT state
422  * -> recvpacket_flag == 0: timeout in this state
423  * -> otherwise: received a packet in this state
424  *
425  * Return conditions as handled by dhclient_state_machine():
426  * Returns 1, sendpacket_flag = 1: send packet, reset timer.
427  * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
428  * Returns 0: finish the nap which was interrupted for no good reason.
429  *
430  * Several per-interface variables are used to keep track of the process:
431  *   active_lease: the lease that is being used on the interface
432  *                 (null pointer if not configured yet).
433  *   offered_leases: leases corresponding to DHCPOFFER messages that have
434  *                   been sent to us by DHCP servers.
435  *   acked_leases: leases corresponding to DHCPACK messages that have been
436  *                 sent to us by DHCP servers.
437  *   sendpacket: DHCP packet we're trying to send.
438  *   destination: IP address to send sendpacket to
439  * In addition, there are several relevant per-lease variables.
440  *   T1_expiry, T2_expiry, lease_expiry: lease milestones
441  * In the active lease, these control the process of renewing the lease;
442  * In leases on the acked_leases list, this simply determines when we
443  * can no longer legitimately use the lease.
444  */
445 void
446 state_reboot(void)
447 {
448         /* If we don't remember an active lease, go straight to INIT. */
449         if (!client->active || client->active->is_bootp) {
450                 state_init();
451                 return;
452         }
453
454         /* We are in the rebooting state. */
455         client->state = S_REBOOTING;
456
457         /* make_request doesn't initialize xid because it normally comes
458            from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
459            so pick an xid now. */
460         client->xid = arc4random();
461
462         /* Make a DHCPREQUEST packet, and set appropriate per-interface
463            flags. */
464         make_request(client->active);
465         client->destination = iaddr_broadcast;
466         client->first_sending = cur_time;
467         client->interval = config->initial_interval;
468
469         /* Zap the medium list... */
470         client->medium = NULL;
471
472         /* Send out the first DHCPREQUEST packet. */
473         send_request();
474 }
475
476 /*
477  * Called when a lease has completely expired and we've
478  * been unable to renew it.
479  */
480 void
481 state_init(void)
482 {
483         /* Make a DHCPDISCOVER packet, and set appropriate per-interface
484            flags. */
485         make_discover(client->active);
486         client->xid = client->packet.xid;
487         client->destination = iaddr_broadcast;
488         client->state = S_SELECTING;
489         client->first_sending = cur_time;
490         client->interval = config->initial_interval;
491
492         /* Add an immediate timeout to cause the first DHCPDISCOVER packet
493            to go out. */
494         send_discover();
495 }
496
497 /*
498  * state_selecting is called when one or more DHCPOFFER packets
499  * have been received and a configurable period of time has passed.
500  */
501 void
502 state_selecting(void)
503 {
504         struct client_lease *lp, *next, *picked;
505
506         /* Cancel state_selecting and send_discover timeouts, since either
507            one could have got us here. */
508         cancel_timeout(state_selecting);
509         cancel_timeout(send_discover);
510
511         /* We have received one or more DHCPOFFER packets.   Currently,
512            the only criterion by which we judge leases is whether or
513            not we get a response when we arp for them. */
514         picked = NULL;
515         for (lp = client->offered_leases; lp; lp = next) {
516                 next = lp->next;
517
518                 /* Check to see if we got an ARPREPLY for the address
519                    in this particular lease. */
520                 if (!picked) {
521                         script_init("ARPCHECK", lp->medium);
522                         script_write_params("check_", lp);
523
524                         /* If the ARPCHECK code detects another
525                            machine using the offered address, it exits
526                            nonzero.  We need to send a DHCPDECLINE and
527                            toss the lease. */
528                         if (script_go()) {
529                                 make_decline(lp);
530                                 send_decline();
531                                 goto freeit;
532                         }
533                         picked = lp;
534                         picked->next = NULL;
535                 } else {
536 freeit:
537                         free_client_lease(lp);
538                 }
539         }
540         client->offered_leases = NULL;
541
542         /* If we just tossed all the leases we were offered, go back
543            to square one. */
544         if (!picked) {
545                 client->state = S_INIT;
546                 state_init();
547                 return;
548         }
549
550         /* If it was a BOOTREPLY, we can just take the address right now. */
551         if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) {
552                 client->new = picked;
553
554                 /* Make up some lease expiry times
555                    XXX these should be configurable. */
556                 client->new->expiry = cur_time + 12000;
557                 client->new->renewal += cur_time + 8000;
558                 client->new->rebind += cur_time + 10000;
559
560                 client->state = S_REQUESTING;
561
562                 /* Bind to the address we received. */
563                 bind_lease();
564                 return;
565         }
566
567         /* Go to the REQUESTING state. */
568         client->destination = iaddr_broadcast;
569         client->state = S_REQUESTING;
570         client->first_sending = cur_time;
571         client->interval = config->initial_interval;
572
573         /* Make a DHCPREQUEST packet from the lease we picked. */
574         make_request(picked);
575         client->xid = client->packet.xid;
576
577         /* Toss the lease we picked - we'll get it back in a DHCPACK. */
578         free_client_lease(picked);
579
580         /* Add an immediate timeout to send the first DHCPREQUEST packet. */
581         send_request();
582 }
583
584 void
585 dhcpack(struct iaddr client_addr, struct option_data *options)
586 {
587         struct client_lease *lease;
588
589
590         if (client->state != S_REBOOTING &&
591             client->state != S_REQUESTING &&
592             client->state != S_RENEWING &&
593             client->state != S_REBINDING)
594                 return;
595
596
597         lease = packet_to_lease(options);
598         if (!lease) {
599                 note("packet_to_lease failed.");
600                 return;
601         }
602
603         client->new = lease;
604
605         /* Stop resending DHCPREQUEST. */
606         cancel_timeout(send_request);
607
608         /* Figure out the lease time. */
609         if (client->new->options[DHO_DHCP_LEASE_TIME].data)
610                 client->new->expiry =
611                     getULong(client->new->options[DHO_DHCP_LEASE_TIME].data);
612         else
613                 client->new->expiry = DEFAULT_LEASE_TIME;
614         /* A number that looks negative here is really just very large,
615            because the lease expiry offset is unsigned. */
616         if (client->new->expiry < 0)
617                 client->new->expiry = TIME_MAX;
618         /* XXX should be fixed by resetting the client state */
619         if (client->new->expiry < 60)
620                 client->new->expiry = 60;
621
622         /* Take the server-provided renewal time if there is one;
623            otherwise figure it out according to the spec. */
624         if (client->new->options[DHO_DHCP_RENEWAL_TIME].len)
625                 client->new->renewal =
626                     getULong(client->new->options[DHO_DHCP_RENEWAL_TIME].data);
627         else
628                 client->new->renewal = client->new->expiry / 2;
629
630         /* Same deal with the rebind time. */
631         if (client->new->options[DHO_DHCP_REBINDING_TIME].len)
632                 client->new->rebind =
633                     getULong(client->new->options[DHO_DHCP_REBINDING_TIME].data);
634         else
635                 client->new->rebind = client->new->renewal +
636                     client->new->renewal / 2 + client->new->renewal / 4;
637
638         client->new->expiry += cur_time;
639         /* Lease lengths can never be negative. */
640         if (client->new->expiry < cur_time)
641                 client->new->expiry = TIME_MAX;
642         client->new->renewal += cur_time;
643         if (client->new->renewal < cur_time)
644                 client->new->renewal = TIME_MAX;
645         client->new->rebind += cur_time;
646         if (client->new->rebind < cur_time)
647                 client->new->rebind = TIME_MAX;
648
649         bind_lease();
650 }
651
652 void
653 bind_lease(void)
654 {
655         /* Remember the medium. */
656         client->new->medium = client->medium;
657
658         /* Write out the new lease. */
659         write_client_lease(client->new, 0);
660
661         /* Run the client script with the new parameters. */
662         script_init((client->state == S_REQUESTING ? "BOUND" :
663             (client->state == S_RENEWING ? "RENEW" :
664             (client->state == S_REBOOTING ? "REBOOT" : "REBIND"))),
665             client->new->medium);
666         if (client->active && client->state != S_REBOOTING)
667                 script_write_params("old_", client->active);
668         script_write_params("new_", client->new);
669         if (client->alias)
670                 script_write_params("alias_", client->alias);
671         script_go();
672
673         /* Replace the old active lease with the new one. */
674         if (client->active)
675                 free_client_lease(client->active);
676         client->active = client->new;
677         client->new = NULL;
678
679         /* Set up a timeout to start the renewal process. */
680         add_timeout(client->active->renewal, state_bound);
681
682         note("bound to %s -- renewal in %ld seconds.",
683             piaddr(client->active->address),
684             client->active->renewal - cur_time);
685         client->state = S_BOUND;
686         reinitialize_interface();
687         go_daemon();
688 }
689
690 /*
691  * state_bound is called when we've successfully bound to a particular
692  * lease, but the renewal time on that lease has expired.   We are
693  * expected to unicast a DHCPREQUEST to the server that gave us our
694  * original lease.
695  */
696 void
697 state_bound(void)
698 {
699         /* T1 has expired. */
700         make_request(client->active);
701         client->xid = client->packet.xid;
702
703         if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
704                 memcpy(client->destination.iabuf,
705                     client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data,
706                     4);
707                 client->destination.len = 4;
708         } else
709                 client->destination = iaddr_broadcast;
710
711         client->first_sending = cur_time;
712         client->interval = config->initial_interval;
713         client->state = S_RENEWING;
714
715         /* Send the first packet immediately. */
716         send_request();
717 }
718
719 void
720 dhcpoffer(struct iaddr client_addr, struct option_data *options)
721 {
722         struct client_lease *lease, *lp;
723         int i;
724         int arp_timeout_needed, stop_selecting;
725         char *name = options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" :
726             "BOOTREPLY";
727
728
729         if (client->state != S_SELECTING)
730                 return;
731
732
733         /* If this lease doesn't supply the minimum required parameters,
734            blow it off. */
735         for (i = 0; config->required_options[i]; i++) {
736                 if (!options[config->required_options[i]].len) {
737                         note("%s isn't satisfactory.", name);
738                         return;
739                 }
740         }
741
742         /* If we've already seen this lease, don't record it again. */
743         for (lease = client->offered_leases;
744             lease; lease = lease->next) {
745                 if (lease->address.len == sizeof(client->packet.yiaddr) &&
746                     !memcmp(lease->address.iabuf,
747                     &client->packet.yiaddr, lease->address.len)) {
748                         debug("%s already seen.", name);
749                         return;
750                 }
751         }
752
753         lease = packet_to_lease(options);
754         if (!lease) {
755                 note("packet_to_lease failed.");
756                 return;
757         }
758
759         /* If this lease was acquired through a BOOTREPLY, record that
760            fact. */
761         if (!options[DHO_DHCP_MESSAGE_TYPE].len)
762                 lease->is_bootp = 1;
763
764         /* Record the medium under which this lease was offered. */
765         lease->medium = client->medium;
766
767         /* Send out an ARP Request for the offered IP address. */
768         script_init("ARPSEND", lease->medium);
769         script_write_params("check_", lease);
770         /* If the script can't send an ARP request without waiting,
771            we'll be waiting when we do the ARPCHECK, so don't wait now. */
772         if (script_go())
773                 arp_timeout_needed = 0;
774         else
775                 arp_timeout_needed = 2;
776
777         /* Figure out when we're supposed to stop selecting. */
778         stop_selecting = client->first_sending + config->select_interval;
779
780         /* If this is the lease we asked for, put it at the head of the
781            list, and don't mess with the arp request timeout. */
782         if (lease->address.len == client->requested_address.len &&
783             !memcmp(lease->address.iabuf,
784             client->requested_address.iabuf,
785             client->requested_address.len)) {
786                 lease->next = client->offered_leases;
787                 client->offered_leases = lease;
788         } else {
789                 /* If we already have an offer, and arping for this
790                    offer would take us past the selection timeout,
791                    then don't extend the timeout - just hope for the
792                    best. */
793                 if (client->offered_leases &&
794                     (cur_time + arp_timeout_needed) > stop_selecting)
795                         arp_timeout_needed = 0;
796
797                 /* Put the lease at the end of the list. */
798                 lease->next = NULL;
799                 if (!client->offered_leases)
800                         client->offered_leases = lease;
801                 else {
802                         for (lp = client->offered_leases; lp->next;
803                             lp = lp->next)
804                                 ;       /* nothing */
805                         lp->next = lease;
806                 }
807         }
808
809         /* If we're supposed to stop selecting before we've had time
810            to wait for the ARPREPLY, add some delay to wait for
811            the ARPREPLY. */
812         if (stop_selecting - cur_time < arp_timeout_needed)
813                 stop_selecting = cur_time + arp_timeout_needed;
814
815         /* If the selecting interval has expired, go immediately to
816            state_selecting().  Otherwise, time out into
817            state_selecting at the select interval. */
818         if (stop_selecting <= 0)
819                 state_selecting();
820         else {
821                 add_timeout(stop_selecting, state_selecting);
822                 cancel_timeout(send_discover);
823         }
824 }
825
826 /*
827  * Allocate a client_lease structure and initialize it from the
828  * parameters in the specified packet.
829  */
830 struct client_lease *
831 packet_to_lease(struct option_data *options)
832 {
833         struct client_lease *lease;
834         int i;
835
836         lease = malloc(sizeof(struct client_lease));
837
838         if (!lease) {
839                 warning("dhcpoffer: no memory to record lease.");
840                 return (NULL);
841         }
842
843         memset(lease, 0, sizeof(*lease));
844
845         /* Copy the lease options. */
846         for (i = 0; i < 256; i++) {
847                 if (options[i].len) {
848                         lease->options[i] = options[i];
849                         options[i].data = NULL;
850                         options[i].len = 0;
851                         if (!check_option(lease, i)) {
852                                 warning("Invalid lease option - ignoring offer");
853                                 free_client_lease(lease);
854                                 return (NULL);
855                         }
856                 }
857         }
858
859         lease->address.len = sizeof(client->packet.yiaddr);
860         memcpy(lease->address.iabuf, &client->packet.yiaddr,
861             lease->address.len);
862
863         /* If the server name was filled out, copy it. */
864         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
865             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
866             client->packet.sname[0]) {
867                 lease->server_name = malloc(DHCP_SNAME_LEN + 1);
868                 if (!lease->server_name) {
869                         warning("dhcpoffer: no memory for server name.");
870                         free_client_lease(lease);
871                         return (NULL);
872                 }
873                 memcpy(lease->server_name, client->packet.sname,
874                     DHCP_SNAME_LEN);
875                 lease->server_name[DHCP_SNAME_LEN] = '\0';
876                 if (!res_hnok(lease->server_name)) {
877                         warning("Bogus server name %s", lease->server_name);
878                         free(lease->server_name);
879                         lease->server_name = NULL;
880                 }
881         }
882
883         /* Ditto for the filename. */
884         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
885             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) &&
886             client->packet.file[0]) {
887                 /* Don't count on the NUL terminator. */
888                 lease->filename = malloc(DHCP_FILE_LEN + 1);
889                 if (!lease->filename) {
890                         warning("dhcpoffer: no memory for filename.");
891                         free_client_lease(lease);
892                         return (NULL);
893                 }
894                 memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN);
895                 lease->filename[DHCP_FILE_LEN] = '\0';
896         }
897         return lease;
898 }
899
900 void
901 dhcpnak(struct iaddr client_addr, struct option_data *options)
902 {
903
904         if (client->state != S_REBOOTING &&
905             client->state != S_REQUESTING &&
906             client->state != S_RENEWING &&
907             client->state != S_REBINDING)
908                 return;
909
910
911         if (!client->active) {
912                 note("DHCPNAK with no active lease.");
913                 return;
914         }
915
916         free_client_lease(client->active);
917         client->active = NULL;
918
919         /* Stop sending DHCPREQUEST packets... */
920         cancel_timeout(send_request);
921
922         client->state = S_INIT;
923         state_init();
924 }
925
926 /*
927  * Send out a DHCPDISCOVER packet, and set a timeout to send out another
928  * one after the right interval has expired.  If we don't get an offer by
929  * the time we reach the panic interval, call the panic function.
930  */
931 void
932 send_discover(void)
933 {
934         int interval, increase = 1;
935
936         /* Figure out how long it's been since we started transmitting. */
937         interval = cur_time - client->first_sending;
938
939         /* If we're past the panic timeout, call the script and tell it
940            we haven't found anything for this interface yet. */
941         if (interval > config->timeout) {
942                 state_panic();
943                 return;
944         }
945
946         /* If we're selecting media, try the whole list before doing
947            the exponential backoff, but if we've already received an
948            offer, stop looping, because we obviously have it right. */
949         if (!client->offered_leases && config->media) {
950                 int fail = 0;
951 again:
952                 if (client->medium) {
953                         client->medium = client->medium->next;
954                         increase = 0;
955                 }
956                 if (!client->medium) {
957                         if (fail)
958                                 error("No valid media types for %s!", ifi->name);
959                         client->medium = config->media;
960                         increase = 1;
961                 }
962
963                 note("Trying medium \"%s\" %d", client->medium->string,
964                     increase);
965                 script_init("MEDIUM", client->medium);
966                 if (script_go())
967                         goto again;
968         }
969
970         /*
971          * If we're supposed to increase the interval, do so.  If it's
972          * currently zero (i.e., we haven't sent any packets yet), set
973          * it to initial_interval; otherwise, add to it a random
974          * number between zero and two times itself.  On average, this
975          * means that it will double with every transmission.
976          */
977         if (increase) {
978                 if (!client->interval)
979                         client->interval = config->initial_interval;
980                 else {
981                         client->interval += (arc4random() >> 2) %
982                             (2 * client->interval);
983                 }
984
985                 /* Don't backoff past cutoff. */
986                 if (client->interval > config->backoff_cutoff)
987                         client->interval = ((config->backoff_cutoff / 2)
988                                  + ((arc4random() >> 2) %
989                                     config->backoff_cutoff));
990         } else if (!client->interval)
991                 client->interval = config->initial_interval;
992
993         /* If the backoff would take us to the panic timeout, just use that
994            as the interval. */
995         if (cur_time + client->interval >
996             client->first_sending + config->timeout)
997                 client->interval = (client->first_sending +
998                          config->timeout) - cur_time + 1;
999
1000         /* Record the number of seconds since we started sending. */
1001         if (interval < 65536)
1002                 client->packet.secs = htons(interval);
1003         else
1004                 client->packet.secs = htons(65535);
1005         client->secs = client->packet.secs;
1006
1007         note("DHCPDISCOVER on %s to %s port %d interval %ld",
1008             ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr),
1009             ntohs(sockaddr_broadcast.sin_port), client->interval);
1010
1011         /* Send out a packet. */
1012         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1013
1014         add_timeout(cur_time + client->interval, send_discover);
1015 }
1016
1017 /*
1018  * state_panic gets called if we haven't received any offers in a preset
1019  * amount of time.   When this happens, we try to use existing leases
1020  * that haven't yet expired, and failing that, we call the client script
1021  * and hope it can do something.
1022  */
1023 void
1024 state_panic(void)
1025 {
1026         struct client_lease *loop = client->active;
1027         struct client_lease *lp;
1028
1029         note("No DHCPOFFERS received.");
1030
1031         /* We may not have an active lease, but we may have some
1032            predefined leases that we can try. */
1033         if (!client->active && client->leases)
1034                 goto activate_next;
1035
1036         /* Run through the list of leases and see if one can be used. */
1037         while (client->active) {
1038                 if (client->active->expiry > cur_time) {
1039                         note("Trying recorded lease %s",
1040                             piaddr(client->active->address));
1041                         /* Run the client script with the existing
1042                            parameters. */
1043                         script_init("TIMEOUT",
1044                             client->active->medium);
1045                         script_write_params("new_", client->active);
1046                         if (client->alias)
1047                                 script_write_params("alias_",
1048                                     client->alias);
1049
1050                         /* If the old lease is still good and doesn't
1051                            yet need renewal, go into BOUND state and
1052                            timeout at the renewal time. */
1053                         if (!script_go()) {
1054                                 if (cur_time <
1055                                     client->active->renewal) {
1056                                         client->state = S_BOUND;
1057                                         note("bound: renewal in %ld seconds.",
1058                                             client->active->renewal -
1059                                             cur_time);
1060                                         add_timeout(client->active->renewal,
1061                                             state_bound);
1062                                 } else {
1063                                         client->state = S_BOUND;
1064                                         note("bound: immediate renewal.");
1065                                         state_bound();
1066                                 }
1067                                 reinitialize_interface();
1068                                 go_daemon();
1069                                 return;
1070                         }
1071                 }
1072
1073                 /* If there are no other leases, give up. */
1074                 if (!client->leases) {
1075                         client->leases = client->active;
1076                         client->active = NULL;
1077                         break;
1078                 }
1079
1080 activate_next:
1081                 /* Otherwise, put the active lease at the end of the
1082                    lease list, and try another lease.. */
1083                 for (lp = client->leases; lp->next; lp = lp->next)
1084                         ;
1085                 lp->next = client->active;
1086                 if (lp->next)
1087                         lp->next->next = NULL;
1088                 client->active = client->leases;
1089                 client->leases = client->leases->next;
1090
1091                 /* If we already tried this lease, we've exhausted the
1092                    set of leases, so we might as well give up for
1093                    now. */
1094                 if (client->active == loop)
1095                         break;
1096                 else if (!loop)
1097                         loop = client->active;
1098         }
1099
1100         /* No leases were available, or what was available didn't work, so
1101            tell the shell script that we failed to allocate an address,
1102            and try again later. */
1103         note("No working leases in persistent database - sleeping.");
1104         script_init("FAIL", NULL);
1105         if (client->alias)
1106                 script_write_params("alias_", client->alias);
1107         script_go();
1108         client->state = S_INIT;
1109         add_timeout(cur_time + config->retry_interval, state_init);
1110         go_daemon();
1111 }
1112
1113 void
1114 send_request(void)
1115 {
1116         struct sockaddr_in destination;
1117         struct in_addr from;
1118         int interval;
1119
1120         /* Figure out how long it's been since we started transmitting. */
1121         interval = cur_time - client->first_sending;
1122
1123         /* If we're in the INIT-REBOOT or REQUESTING state and we're
1124            past the reboot timeout, go to INIT and see if we can
1125            DISCOVER an address... */
1126         /* XXX In the INIT-REBOOT state, if we don't get an ACK, it
1127            means either that we're on a network with no DHCP server,
1128            or that our server is down.  In the latter case, assuming
1129            that there is a backup DHCP server, DHCPDISCOVER will get
1130            us a new address, but we could also have successfully
1131            reused our old address.  In the former case, we're hosed
1132            anyway.  This is not a win-prone situation. */
1133         if ((client->state == S_REBOOTING ||
1134             client->state == S_REQUESTING) &&
1135             interval > config->reboot_timeout) {
1136 cancel:
1137                 client->state = S_INIT;
1138                 cancel_timeout(send_request);
1139                 state_init();
1140                 return;
1141         }
1142
1143         /* If we're in the reboot state, make sure the media is set up
1144            correctly. */
1145         if (client->state == S_REBOOTING &&
1146             !client->medium &&
1147             client->active->medium) {
1148                 script_init("MEDIUM", client->active->medium);
1149
1150                 /* If the medium we chose won't fly, go to INIT state. */
1151                 if (script_go())
1152                         goto cancel;
1153
1154                 /* Record the medium. */
1155                 client->medium = client->active->medium;
1156         }
1157
1158         /* If the lease has expired, relinquish the address and go back
1159            to the INIT state. */
1160         if (client->state != S_REQUESTING &&
1161             cur_time > client->active->expiry) {
1162                 /* Run the client script with the new parameters. */
1163                 script_init("EXPIRE", NULL);
1164                 script_write_params("old_", client->active);
1165                 if (client->alias)
1166                         script_write_params("alias_", client->alias);
1167                 script_go();
1168
1169                 /* Now do a preinit on the interface so that we can
1170                    discover a new address. */
1171                 script_init("PREINIT", NULL);
1172                 if (client->alias)
1173                         script_write_params("alias_", client->alias);
1174                 script_go();
1175
1176                 client->state = S_INIT;
1177                 state_init();
1178                 return;
1179         }
1180
1181         /* Do the exponential backoff... */
1182         if (!client->interval)
1183                 client->interval = config->initial_interval;
1184         else
1185                 client->interval += ((arc4random() >> 2) %
1186                     (2 * client->interval));
1187
1188         /* Don't backoff past cutoff. */
1189         if (client->interval > config->backoff_cutoff)
1190                 client->interval = ((config->backoff_cutoff / 2) +
1191                     ((arc4random() >> 2) % client->interval));
1192
1193         /* If the backoff would take us to the expiry time, just set the
1194            timeout to the expiry time. */
1195         if (client->state != S_REQUESTING && cur_time + client->interval >
1196             client->active->expiry)
1197                 client->interval = client->active->expiry - cur_time + 1;
1198
1199         /* If the lease T2 time has elapsed, or if we're not yet bound,
1200            broadcast the DHCPREQUEST rather than unicasting. */
1201         memset(&destination, 0, sizeof(destination));
1202         if (client->state == S_REQUESTING ||
1203             client->state == S_REBOOTING ||
1204             cur_time > client->active->rebind)
1205                 destination.sin_addr.s_addr = INADDR_BROADCAST;
1206         else
1207                 memcpy(&destination.sin_addr.s_addr, client->destination.iabuf,
1208                     sizeof(destination.sin_addr.s_addr));
1209         destination.sin_port = htons(REMOTE_PORT);
1210         destination.sin_family = AF_INET;
1211         destination.sin_len = sizeof(destination);
1212
1213         if (client->state != S_REQUESTING)
1214                 memcpy(&from, client->active->address.iabuf, sizeof(from));
1215         else
1216                 from.s_addr = INADDR_ANY;
1217
1218         /* Record the number of seconds since we started sending. */
1219         if (client->state == S_REQUESTING)
1220                 client->packet.secs = client->secs;
1221         else {
1222                 if (interval < 65536)
1223                         client->packet.secs = htons(interval);
1224                 else
1225                         client->packet.secs = htons(65535);
1226         }
1227
1228         note("DHCPREQUEST on %s to %s port %d", ifi->name,
1229             inet_ntoa(destination.sin_addr), ntohs(destination.sin_port));
1230
1231         /* Send out a packet. */
1232         send_packet(from, &destination, NULL);
1233
1234         add_timeout(cur_time + client->interval, send_request);
1235 }
1236
1237 void
1238 send_decline(void)
1239 {
1240         note("DHCPDECLINE on %s to %s port %d", ifi->name,
1241             inet_ntoa(sockaddr_broadcast.sin_addr),
1242             ntohs(sockaddr_broadcast.sin_port));
1243
1244         /* Send out a packet. */
1245         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1246 }
1247
1248 void
1249 make_discover(struct client_lease *lease)
1250 {
1251         unsigned char discover = DHCPDISCOVER;
1252         struct option_data options[256];
1253         int i;
1254
1255         memset(options, 0, sizeof(options));
1256         memset(&client->packet, 0, sizeof(client->packet));
1257
1258         /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */
1259         i = DHO_DHCP_MESSAGE_TYPE;
1260         options[i].data = &discover;
1261         options[i].len = sizeof(discover);
1262
1263         /* Request the options we want */
1264         i  = DHO_DHCP_PARAMETER_REQUEST_LIST;
1265         options[i].data = config->requested_options;
1266         options[i].len = config->requested_option_count;
1267
1268         /* If we had an address, try to get it again. */
1269         if (lease) {
1270                 client->requested_address = lease->address;
1271                 i = DHO_DHCP_REQUESTED_ADDRESS;
1272                 options[i].data = lease->address.iabuf;
1273                 options[i].len = lease->address.len;
1274         } else
1275                 client->requested_address.len = 0;
1276
1277         /* Send any options requested in the config file. */
1278         for (i = 0; i < 256; i++)
1279                 if (!options[i].data &&
1280                     config->send_options[i].data) {
1281                         options[i].data = config->send_options[i].data;
1282                         options[i].len = config->send_options[i].len;
1283                 }
1284
1285         /* Set up the option buffer to fit in a minimal UDP packet. */
1286         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1287             options);
1288         if (i == -1 || client->packet.options[i] != DHO_END)
1289                 error("options do not fit in DHCPDISCOVER packet.");
1290         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1291         if (client->packet_length < BOOTP_MIN_LEN)
1292                 client->packet_length = BOOTP_MIN_LEN;
1293
1294         client->packet.op = BOOTREQUEST;
1295         client->packet.htype = ifi->hw_address.htype;
1296         client->packet.hlen = ifi->hw_address.hlen;
1297         client->packet.hops = 0;
1298         client->packet.xid = arc4random();
1299         client->packet.secs = 0; /* filled in by send_discover. */
1300         client->packet.flags = 0;
1301
1302         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1303         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1304         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1305         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1306         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1307             ifi->hw_address.hlen);
1308 }
1309
1310 void
1311 make_request(struct client_lease * lease)
1312 {
1313         unsigned char request = DHCPREQUEST;
1314         struct option_data options[256];
1315         int i;
1316
1317         memset(options, 0, sizeof(options));
1318         memset(&client->packet, 0, sizeof(client->packet));
1319
1320         /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
1321         i = DHO_DHCP_MESSAGE_TYPE;
1322         options[i].data = &request;
1323         options[i].len = sizeof(request);
1324
1325         /* Request the options we want */
1326         i = DHO_DHCP_PARAMETER_REQUEST_LIST;
1327         options[i].data = config->requested_options;
1328         options[i].len = config->requested_option_count;
1329
1330         /* If we are requesting an address that hasn't yet been assigned
1331            to us, use the DHCP Requested Address option. */
1332         if (client->state == S_REQUESTING) {
1333                 /* Send back the server identifier... */
1334                 i = DHO_DHCP_SERVER_IDENTIFIER;
1335                 options[i].data = lease->options[i].data;
1336                 options[i].len = lease->options[i].len;
1337         }
1338         if (client->state == S_REQUESTING ||
1339             client->state == S_REBOOTING) {
1340                 client->requested_address = lease->address;
1341                 i = DHO_DHCP_REQUESTED_ADDRESS;
1342                 options[i].data = lease->address.iabuf;
1343                 options[i].len = lease->address.len;
1344         } else
1345                 client->requested_address.len = 0;
1346
1347         /* Send any options requested in the config file. */
1348         for (i = 0; i < 256; i++)
1349                 if (!options[i].data && config->send_options[i].data) {
1350                         options[i].data = config->send_options[i].data;
1351                         options[i].len = config->send_options[i].len;
1352                 }
1353
1354         /* Set up the option buffer to fit in a minimal UDP packet. */
1355         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1356             options);
1357         if (i == -1 || client->packet.options[i] != DHO_END)
1358                 error("options do not fit in DHCPREQUEST packet.");
1359         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1360         if (client->packet_length < BOOTP_MIN_LEN)
1361                 client->packet_length = BOOTP_MIN_LEN;
1362
1363         client->packet.op = BOOTREQUEST;
1364         client->packet.htype = ifi->hw_address.htype;
1365         client->packet.hlen = ifi->hw_address.hlen;
1366         client->packet.hops = 0;
1367         client->packet.xid = client->xid;
1368         client->packet.secs = 0; /* Filled in by send_request. */
1369         client->packet.flags = 0;
1370
1371         /* If we own the address we're requesting, put it in ciaddr;
1372            otherwise set ciaddr to zero. */
1373         if (client->state == S_BOUND ||
1374             client->state == S_RENEWING ||
1375             client->state == S_REBINDING) {
1376                 memcpy(&client->packet.ciaddr,
1377                     lease->address.iabuf, lease->address.len);
1378         } else {
1379                 memset(&client->packet.ciaddr, 0,
1380                     sizeof(client->packet.ciaddr));
1381         }
1382
1383         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1384         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1385         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1386         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1387             ifi->hw_address.hlen);
1388 }
1389
1390 void
1391 make_decline(struct client_lease *lease)
1392 {
1393         struct option_data options[256];
1394         unsigned char decline = DHCPDECLINE;
1395         int i;
1396
1397         memset(options, 0, sizeof(options));
1398         memset(&client->packet, 0, sizeof(client->packet));
1399
1400         /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */
1401         i = DHO_DHCP_MESSAGE_TYPE;
1402         options[i].data = &decline;
1403         options[i].len = sizeof(decline);
1404
1405         /* Send back the server identifier... */
1406         i = DHO_DHCP_SERVER_IDENTIFIER;
1407         options[i].data = lease->options[i].data;
1408         options[i].len = lease->options[i].len;
1409
1410         /* Send back the address we're declining. */
1411         i = DHO_DHCP_REQUESTED_ADDRESS;
1412         options[i].data = lease->address.iabuf;
1413         options[i].len = lease->address.len;
1414
1415         /* Send the uid if the user supplied one. */
1416         i = DHO_DHCP_CLIENT_IDENTIFIER;
1417         if (config->send_options[i].len) {
1418                 options[i].data = config->send_options[i].data;
1419                 options[i].len = config->send_options[i].len;
1420         }
1421
1422         /* Set up the option buffer to fit in a minimal UDP packet. */
1423         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1424             options);
1425         if (i == -1 || client->packet.options[i] != DHO_END)
1426                 error("options do not fit in DHCPDECLINE packet.");
1427         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1428         if (client->packet_length < BOOTP_MIN_LEN)
1429                 client->packet_length = BOOTP_MIN_LEN;
1430
1431         client->packet.op = BOOTREQUEST;
1432         client->packet.htype = ifi->hw_address.htype;
1433         client->packet.hlen = ifi->hw_address.hlen;
1434         client->packet.hops = 0;
1435         client->packet.xid = client->xid;
1436         client->packet.secs = 0; /* Filled in by send_request. */
1437         client->packet.flags = 0;
1438
1439         /* ciaddr must always be zero. */
1440         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1441         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1442         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1443         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1444         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1445             ifi->hw_address.hlen);
1446 }
1447
1448 void
1449 free_client_lease(struct client_lease *lease)
1450 {
1451         int i;
1452
1453         if (lease->server_name)
1454                 free(lease->server_name);
1455         if (lease->filename)
1456                 free(lease->filename);
1457         for (i = 0; i < 256; i++) {
1458                 if (lease->options[i].len)
1459                         free(lease->options[i].data);
1460         }
1461         free(lease);
1462 }
1463
1464 void
1465 rewrite_client_leases(void)
1466 {
1467         struct client_lease *lp;
1468
1469         if (!leaseFile) /* XXX */
1470                 error("lease file not open");
1471
1472         fflush(leaseFile);
1473         rewind(leaseFile);
1474
1475         for (lp = client->leases; lp; lp = lp->next)
1476                 write_client_lease(lp, 1);
1477         if (client->active)
1478                 write_client_lease(client->active, 1);
1479
1480         fflush(leaseFile);
1481         ftruncate(fileno(leaseFile), ftello(leaseFile));
1482         fsync(fileno(leaseFile));
1483 }
1484
1485 void
1486 write_client_lease(struct client_lease *lease, int rewrite)
1487 {
1488         static int leases_written;
1489         struct tm *t;
1490         int i;
1491
1492         if (!rewrite) {
1493                 if (leases_written++ > 20) {
1494                         rewrite_client_leases();
1495                         leases_written = 0;
1496                 }
1497         }
1498
1499         /* If the lease came from the config file, we don't need to stash
1500            a copy in the lease database. */
1501         if (lease->is_static)
1502                 return;
1503
1504         if (!leaseFile) /* XXX */
1505                 error("lease file not open");
1506
1507         fprintf(leaseFile, "lease {\n");
1508         if (lease->is_bootp)
1509                 fprintf(leaseFile, "  bootp;\n");
1510         fprintf(leaseFile, "  interface \"%s\";\n", ifi->name);
1511         fprintf(leaseFile, "  fixed-address %s;\n", piaddr(lease->address));
1512         if (lease->filename)
1513                 fprintf(leaseFile, "  filename \"%s\";\n", lease->filename);
1514         if (lease->server_name)
1515                 fprintf(leaseFile, "  server-name \"%s\";\n",
1516                     lease->server_name);
1517         if (lease->medium)
1518                 fprintf(leaseFile, "  medium \"%s\";\n", lease->medium->string);
1519         for (i = 0; i < 256; i++)
1520                 if (lease->options[i].len)
1521                         fprintf(leaseFile, "  option %s %s;\n",
1522                             dhcp_options[i].name,
1523                             pretty_print_option(i, lease->options[i].data,
1524                             lease->options[i].len, 1, 1));
1525
1526         t = gmtime(&lease->renewal);
1527         fprintf(leaseFile, "  renew %d %d/%d/%d %02d:%02d:%02d;\n",
1528             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1529             t->tm_hour, t->tm_min, t->tm_sec);
1530         t = gmtime(&lease->rebind);
1531         fprintf(leaseFile, "  rebind %d %d/%d/%d %02d:%02d:%02d;\n",
1532             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1533             t->tm_hour, t->tm_min, t->tm_sec);
1534         t = gmtime(&lease->expiry);
1535         fprintf(leaseFile, "  expire %d %d/%d/%d %02d:%02d:%02d;\n",
1536             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1537             t->tm_hour, t->tm_min, t->tm_sec);
1538         fprintf(leaseFile, "}\n");
1539         fflush(leaseFile);
1540 }
1541
1542 void
1543 script_init(char *reason, struct string_list *medium)
1544 {
1545         size_t           len, mediumlen = 0;
1546         struct imsg_hdr  hdr;
1547         struct buf      *buf;
1548
1549         if (medium != NULL && medium->string != NULL)
1550                 mediumlen = strlen(medium->string);
1551
1552         hdr.code = IMSG_SCRIPT_INIT;
1553         hdr.len = sizeof(struct imsg_hdr) +
1554             sizeof(size_t) + mediumlen +
1555             sizeof(size_t) + strlen(reason);
1556
1557         buf = buf_open(hdr.len);
1558
1559         buf_add(buf, &hdr, sizeof(hdr));
1560         buf_add(buf, &mediumlen, sizeof(mediumlen));
1561         if (mediumlen > 0)
1562                 buf_add(buf, medium->string, mediumlen);
1563         len = strlen(reason);
1564         buf_add(buf, &len, sizeof(len));
1565         buf_add(buf, reason, len);
1566
1567         buf_close(privfd, buf);
1568 }
1569
1570 void
1571 priv_script_init(char *reason, char *medium)
1572 {
1573         client->scriptEnvsize = 100;
1574         if (client->scriptEnv == NULL)
1575                 client->scriptEnv =
1576                     calloc(client->scriptEnvsize, sizeof(char *));
1577         if (client->scriptEnv == NULL)
1578                 error("script_init: no memory for environment");
1579
1580         client->scriptEnv[0] = strdup(CLIENT_PATH);
1581         if (client->scriptEnv[0] == NULL)
1582                 error("script_init: no memory for environment");
1583
1584         client->scriptEnv[1] = NULL;
1585
1586         script_set_env("", "interface", ifi->name);
1587
1588         if (medium)
1589                 script_set_env("", "medium", medium);
1590
1591         script_set_env("", "reason", reason);
1592 }
1593
1594 void
1595 priv_script_write_params(char *prefix, struct client_lease *lease)
1596 {
1597         u_int8_t dbuf[1500];
1598         int i, len = 0;
1599         char tbuf[128];
1600
1601         script_set_env(prefix, "ip_address", piaddr(lease->address));
1602
1603         if (lease->options[DHO_SUBNET_MASK].len &&
1604             (lease->options[DHO_SUBNET_MASK].len <
1605             sizeof(lease->address.iabuf))) {
1606                 struct iaddr netmask, subnet, broadcast;
1607
1608                 memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data,
1609                     lease->options[DHO_SUBNET_MASK].len);
1610                 netmask.len = lease->options[DHO_SUBNET_MASK].len;
1611
1612                 subnet = subnet_number(lease->address, netmask);
1613                 if (subnet.len) {
1614                         script_set_env(prefix, "network_number",
1615                             piaddr(subnet));
1616                         if (!lease->options[DHO_BROADCAST_ADDRESS].len) {
1617                                 broadcast = broadcast_addr(subnet, netmask);
1618                                 if (broadcast.len)
1619                                         script_set_env(prefix,
1620                                             "broadcast_address",
1621                                             piaddr(broadcast));
1622                         }
1623                 }
1624         }
1625
1626         if (lease->filename)
1627                 script_set_env(prefix, "filename", lease->filename);
1628         if (lease->server_name)
1629                 script_set_env(prefix, "server_name",
1630                     lease->server_name);
1631         for (i = 0; i < 256; i++) {
1632                 u_int8_t *dp = NULL;
1633
1634                 if (config->defaults[i].len) {
1635                         if (lease->options[i].len) {
1636                                 switch (config->default_actions[i]) {
1637                                 case ACTION_DEFAULT:
1638                                         dp = lease->options[i].data;
1639                                         len = lease->options[i].len;
1640                                         break;
1641                                 case ACTION_SUPERSEDE:
1642 supersede:
1643                                         dp = config->defaults[i].data;
1644                                         len = config->defaults[i].len;
1645                                         break;
1646                                 case ACTION_PREPEND:
1647                                         len = config->defaults[i].len +
1648                                             lease->options[i].len;
1649                                         if (len > sizeof(dbuf)) {
1650                                                 warning("no space to %s %s",
1651                                                     "prepend option",
1652                                                     dhcp_options[i].name);
1653                                                 goto supersede;
1654                                         }
1655                                         dp = dbuf;
1656                                         memcpy(dp,
1657                                             config->defaults[i].data,
1658                                             config->defaults[i].len);
1659                                         memcpy(dp +
1660                                             config->defaults[i].len,
1661                                             lease->options[i].data,
1662                                             lease->options[i].len);
1663                                         dp[len] = '\0';
1664                                         break;
1665                                 case ACTION_APPEND:
1666                                         len = config->defaults[i].len +
1667                                             lease->options[i].len;
1668                                         if (len > sizeof(dbuf)) {
1669                                                 warning("no space to %s %s",
1670                                                     "append option",
1671                                                     dhcp_options[i].name);
1672                                                 goto supersede;
1673                                         }
1674                                         dp = dbuf;
1675                                         memcpy(dp, lease->options[i].data,
1676                                             lease->options[i].len);
1677                                         memcpy(dp + lease->options[i].len,
1678                                             config->defaults[i].data,
1679                                             config->defaults[i].len);
1680                                         dp[len] = '\0';
1681                                 }
1682                         } else {
1683                                 dp = config->defaults[i].data;
1684                                 len = config->defaults[i].len;
1685                         }
1686                 } else if (lease->options[i].len) {
1687                         len = lease->options[i].len;
1688                         dp = lease->options[i].data;
1689                 } else {
1690                         len = 0;
1691                 }
1692                 if (len) {
1693                         char name[256];
1694
1695                         if (dhcp_option_ev_name(name, sizeof(name),
1696                             &dhcp_options[i]))
1697                                 script_set_env(prefix, name,
1698                                     pretty_print_option(i, dp, len, 0, 0));
1699                 }
1700         }
1701         snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry);
1702         script_set_env(prefix, "expiry", tbuf);
1703 }
1704
1705 void
1706 script_write_params(char *prefix, struct client_lease *lease)
1707 {
1708         size_t           fn_len = 0, sn_len = 0, pr_len = 0;
1709         struct imsg_hdr  hdr;
1710         struct buf      *buf;
1711         int              i;
1712
1713         if (lease->filename != NULL)
1714                 fn_len = strlen(lease->filename);
1715         if (lease->server_name != NULL)
1716                 sn_len = strlen(lease->server_name);
1717         if (prefix != NULL)
1718                 pr_len = strlen(prefix);
1719
1720         hdr.code = IMSG_SCRIPT_WRITE_PARAMS;
1721         hdr.len = sizeof(hdr) + sizeof(struct client_lease) +
1722             sizeof(size_t) + fn_len + sizeof(size_t) + sn_len +
1723             sizeof(size_t) + pr_len;
1724
1725         for (i = 0; i < 256; i++)
1726                 hdr.len += sizeof(int) + lease->options[i].len;
1727
1728         scripttime = time(NULL);
1729
1730         buf = buf_open(hdr.len);
1731
1732         buf_add(buf, &hdr, sizeof(hdr));
1733         buf_add(buf, lease, sizeof(struct client_lease));
1734         buf_add(buf, &fn_len, sizeof(fn_len));
1735         buf_add(buf, lease->filename, fn_len);
1736         buf_add(buf, &sn_len, sizeof(sn_len));
1737         buf_add(buf, lease->server_name, sn_len);
1738         buf_add(buf, &pr_len, sizeof(pr_len));
1739         buf_add(buf, prefix, pr_len);
1740
1741         for (i = 0; i < 256; i++) {
1742                 buf_add(buf, &lease->options[i].len,
1743                     sizeof(lease->options[i].len));
1744                 buf_add(buf, lease->options[i].data,
1745                     lease->options[i].len);
1746         }
1747
1748         buf_close(privfd, buf);
1749 }
1750
1751 int
1752 script_go(void)
1753 {
1754         struct imsg_hdr  hdr;
1755         struct buf      *buf;
1756         int              ret;
1757
1758         scripttime = time(NULL);
1759
1760         hdr.code = IMSG_SCRIPT_GO;
1761         hdr.len = sizeof(struct imsg_hdr);
1762
1763         buf = buf_open(hdr.len);
1764
1765         buf_add(buf, &hdr, sizeof(hdr));
1766         buf_close(privfd, buf);
1767
1768         bzero(&hdr, sizeof(hdr));
1769         buf_read(privfd, &hdr, sizeof(hdr));
1770         if (hdr.code != IMSG_SCRIPT_GO_RET)
1771                 error("unexpected msg type %u", hdr.code);
1772         if (hdr.len != sizeof(hdr) + sizeof(int))
1773                 error("received corrupted message");
1774         buf_read(privfd, &ret, sizeof(ret));
1775
1776         return (ret);
1777 }
1778
1779 int
1780 priv_script_go(void)
1781 {
1782         char *scriptName, *argv[2], **envp;
1783         int pid, wpid, wstatus;
1784
1785         scripttime = time(NULL);
1786
1787         scriptName = config->script_name;
1788         envp = client->scriptEnv;
1789
1790         argv[0] = scriptName;
1791         argv[1] = NULL;
1792
1793         pid = fork();
1794         if (pid < 0) {
1795                 error("fork: %m");
1796                 wstatus = 0;
1797         } else if (pid) {
1798                 do {
1799                         wpid = wait(&wstatus);
1800                 } while (wpid != pid && wpid > 0);
1801                 if (wpid < 0) {
1802                         error("wait: %m");
1803                         wstatus = 0;
1804                 }
1805         } else {
1806                 execve(scriptName, argv, envp);
1807                 error("execve (%s, ...): %m", scriptName);
1808         }
1809
1810         script_flush_env();
1811
1812         return (WEXITSTATUS(wstatus));
1813 }
1814
1815 void
1816 script_set_env(const char *prefix, const char *name, const char *value)
1817 {
1818         int i, j, namelen;
1819
1820         namelen = strlen(name);
1821
1822         for (i = 0; client->scriptEnv[i]; i++)
1823                 if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
1824                     client->scriptEnv[i][namelen] == '=')
1825                         break;
1826
1827         if (client->scriptEnv[i])
1828                 /* Reuse the slot. */
1829                 free(client->scriptEnv[i]);
1830         else {
1831                 /* New variable.  Expand if necessary. */
1832                 if (i >= client->scriptEnvsize - 1) {
1833                         char **newscriptEnv;
1834                         int newscriptEnvsize = client->scriptEnvsize + 50;
1835
1836                         newscriptEnv = realloc(client->scriptEnv,
1837                             newscriptEnvsize);
1838                         if (newscriptEnv == NULL) {
1839                                 free(client->scriptEnv);
1840                                 client->scriptEnv = NULL;
1841                                 client->scriptEnvsize = 0;
1842                                 error("script_set_env: no memory for variable");
1843                         }
1844                         client->scriptEnv = newscriptEnv;
1845                         client->scriptEnvsize = newscriptEnvsize;
1846                 }
1847                 /* need to set the NULL pointer at end of array beyond
1848                    the new slot. */
1849                 client->scriptEnv[i + 1] = NULL;
1850         }
1851         /* Allocate space and format the variable in the appropriate slot. */
1852         client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
1853             strlen(value) + 1);
1854         if (client->scriptEnv[i] == NULL)
1855                 error("script_set_env: no memory for variable assignment");
1856
1857         /* No `` or $() command substitution allowed in environment values! */
1858         for (j = 0; j < strlen(value); j++)
1859                 switch (value[j]) {
1860                 case '`':
1861                 case '$':
1862                         error("illegal character (%c) in value '%s'", value[j],
1863                             value);
1864                         /* not reached */
1865                 }
1866         snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1867             1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
1868 }
1869
1870 void
1871 script_flush_env(void)
1872 {
1873         int i;
1874
1875         for (i = 0; client->scriptEnv[i]; i++) {
1876                 free(client->scriptEnv[i]);
1877                 client->scriptEnv[i] = NULL;
1878         }
1879         client->scriptEnvsize = 0;
1880 }
1881
1882 int
1883 dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option)
1884 {
1885         size_t i;
1886
1887         for (i = 0; option->name[i]; i++) {
1888                 if (i + 1 == buflen)
1889                         return 0;
1890                 if (option->name[i] == '-')
1891                         buf[i] = '_';
1892                 else
1893                         buf[i] = option->name[i];
1894         }
1895
1896         buf[i] = 0;
1897         return 1;
1898 }
1899
1900 void
1901 go_daemon(void)
1902 {
1903         static int state = 0;
1904
1905         if (no_daemon || state)
1906                 return;
1907
1908         state = 1;
1909
1910         /* Stop logging to stderr... */
1911         log_perror = 0;
1912
1913         if (daemon(1, 0) == -1)
1914                 error("daemon");
1915
1916         /* we are chrooted, daemon(3) fails to open /dev/null */
1917         if (nullfd != -1) {
1918                 dup2(nullfd, STDIN_FILENO);
1919                 dup2(nullfd, STDOUT_FILENO);
1920                 dup2(nullfd, STDERR_FILENO);
1921                 close(nullfd);
1922                 nullfd = -1;
1923         }
1924 }
1925
1926 int
1927 check_option(struct client_lease *l, int option)
1928 {
1929         char *opbuf;
1930         char *sbuf;
1931
1932         /* we use this, since this is what gets passed to dhclient-script */
1933
1934         opbuf = pretty_print_option(option, l->options[option].data,
1935             l->options[option].len, 0, 0);
1936
1937         sbuf = option_as_string(option, l->options[option].data,
1938             l->options[option].len);
1939
1940         switch (option) {
1941         case DHO_SUBNET_MASK:
1942         case DHO_TIME_SERVERS:
1943         case DHO_NAME_SERVERS:
1944         case DHO_ROUTERS:
1945         case DHO_DOMAIN_NAME_SERVERS:
1946         case DHO_LOG_SERVERS:
1947         case DHO_COOKIE_SERVERS:
1948         case DHO_LPR_SERVERS:
1949         case DHO_IMPRESS_SERVERS:
1950         case DHO_RESOURCE_LOCATION_SERVERS:
1951         case DHO_SWAP_SERVER:
1952         case DHO_BROADCAST_ADDRESS:
1953         case DHO_NIS_SERVERS:
1954         case DHO_NTP_SERVERS:
1955         case DHO_NETBIOS_NAME_SERVERS:
1956         case DHO_NETBIOS_DD_SERVER:
1957         case DHO_FONT_SERVERS:
1958         case DHO_DHCP_SERVER_IDENTIFIER:
1959                 if (!ipv4addrs(opbuf)) {
1960                         warning("Invalid IP address in option: %s", opbuf);
1961                         return (0);
1962                 }
1963                 return (1);
1964         case DHO_HOST_NAME:
1965         case DHO_DOMAIN_NAME:
1966         case DHO_NIS_DOMAIN:
1967                 if (!res_hnok(sbuf)) {
1968                         warning("Bogus Host Name option %d: %s (%s)", option,
1969                             sbuf, opbuf);
1970                         l->options[option].len = 0;
1971                         free(l->options[option].data);
1972                 }
1973                 return (1);
1974         case DHO_PAD:
1975         case DHO_TIME_OFFSET:
1976         case DHO_BOOT_SIZE:
1977         case DHO_MERIT_DUMP:
1978         case DHO_ROOT_PATH:
1979         case DHO_EXTENSIONS_PATH:
1980         case DHO_IP_FORWARDING:
1981         case DHO_NON_LOCAL_SOURCE_ROUTING:
1982         case DHO_POLICY_FILTER:
1983         case DHO_MAX_DGRAM_REASSEMBLY:
1984         case DHO_DEFAULT_IP_TTL:
1985         case DHO_PATH_MTU_AGING_TIMEOUT:
1986         case DHO_PATH_MTU_PLATEAU_TABLE:
1987         case DHO_INTERFACE_MTU:
1988         case DHO_ALL_SUBNETS_LOCAL:
1989         case DHO_PERFORM_MASK_DISCOVERY:
1990         case DHO_MASK_SUPPLIER:
1991         case DHO_ROUTER_DISCOVERY:
1992         case DHO_ROUTER_SOLICITATION_ADDRESS:
1993         case DHO_STATIC_ROUTES:
1994         case DHO_TRAILER_ENCAPSULATION:
1995         case DHO_ARP_CACHE_TIMEOUT:
1996         case DHO_IEEE802_3_ENCAPSULATION:
1997         case DHO_DEFAULT_TCP_TTL:
1998         case DHO_TCP_KEEPALIVE_INTERVAL:
1999         case DHO_TCP_KEEPALIVE_GARBAGE:
2000         case DHO_VENDOR_ENCAPSULATED_OPTIONS:
2001         case DHO_NETBIOS_NODE_TYPE:
2002         case DHO_NETBIOS_SCOPE:
2003         case DHO_X_DISPLAY_MANAGER:
2004         case DHO_DHCP_REQUESTED_ADDRESS:
2005         case DHO_DHCP_LEASE_TIME:
2006         case DHO_DHCP_OPTION_OVERLOAD:
2007         case DHO_DHCP_MESSAGE_TYPE:
2008         case DHO_DHCP_PARAMETER_REQUEST_LIST:
2009         case DHO_DHCP_MESSAGE:
2010         case DHO_DHCP_MAX_MESSAGE_SIZE:
2011         case DHO_DHCP_RENEWAL_TIME:
2012         case DHO_DHCP_REBINDING_TIME:
2013         case DHO_DHCP_CLASS_IDENTIFIER:
2014         case DHO_DHCP_CLIENT_IDENTIFIER:
2015         case DHO_DHCP_USER_CLASS_ID:
2016         case DHO_END:
2017                 return (1);
2018         default:
2019                 warning("unknown dhcp option value 0x%x", option);
2020                 return (unknown_ok);
2021         }
2022 }
2023
2024 int
2025 res_hnok(const char *name)
2026 {
2027         const char *dn = name;
2028         int pch = '.', ch = *dn++;
2029         int warn = 0;
2030
2031         while (ch != '\0') {
2032                 int nch = *dn++;
2033
2034                 if (ch == '.') {
2035                         ;
2036                 } else if (pch == '.' || nch == '.' || nch == '\0') {
2037                         if (!isalnum(ch))
2038                                 return (0);
2039                 } else if (!isalnum(ch) && ch != '-' && ch != '_')
2040                                 return (0);
2041                 else if (ch == '_' && warn == 0) {
2042                         warning("warning: hostname %s contains an "
2043                             "underscore which violates RFC 952", name);
2044                         warn++;
2045                 }
2046                 pch = ch, ch = nch;
2047         }
2048         return (1);
2049 }
2050
2051 /* Does buf consist only of dotted decimal ipv4 addrs?
2052  * return how many if so,
2053  * otherwise, return 0
2054  */
2055 int
2056 ipv4addrs(char * buf)
2057 {
2058         struct in_addr jnk;
2059         int count = 0;
2060
2061         while (inet_aton(buf, &jnk) == 1){
2062                 count++;
2063                 while (*buf == '.' || isdigit(*buf))
2064                         buf++;
2065                 if (*buf == '\0')
2066                         return (count);
2067                 while (*buf ==  ' ')
2068                         buf++;
2069         }
2070         return (0);
2071 }
2072
2073 char *
2074 option_as_string(unsigned int code, unsigned char *data, int len)
2075 {
2076         static char optbuf[32768]; /* XXX */
2077         char *op = optbuf;
2078         int opleft = sizeof(optbuf);
2079         unsigned char *dp = data;
2080
2081         if (code > 255)
2082                 error("option_as_string: bad code %d", code);
2083
2084         for (; dp < data + len; dp++) {
2085                 if (!isascii(*dp) || !isprint(*dp)) {
2086                         if (dp + 1 != data + len || *dp != 0) {
2087                                 size_t oplen;
2088                                 snprintf(op, opleft, "\\%03o", *dp);
2089                                 oplen = strlen(op);
2090                                 op += oplen;
2091                                 opleft -= oplen;
2092                         }
2093                 } else if (*dp == '"' || *dp == '\'' || *dp == '$' ||
2094                     *dp == '`' || *dp == '\\') {
2095                         *op++ = '\\';
2096                         *op++ = *dp;
2097                         opleft -= 2;
2098                 } else {
2099                         *op++ = *dp;
2100                         opleft--;
2101                 }
2102         }
2103         if (opleft < 1)
2104                 goto toobig;
2105         *op = 0;
2106         return optbuf;
2107 toobig:
2108         warning("dhcp option too large");
2109         return "<error>";
2110 }
2111
2112 int
2113 fork_privchld(int fd, int fd2)
2114 {
2115         struct pollfd pfd[1];
2116         int nfds, pfail = 0;
2117
2118         switch (fork()) {
2119         case -1:
2120                 error("cannot fork");
2121                 break;
2122         case 0:
2123                 break;
2124         default:
2125                 return (0);
2126         }
2127
2128         if (chdir("/") == -1)
2129                 error("chdir(\"/\")");
2130
2131         setproctitle("%s [priv]", ifi->name);
2132
2133         dup2(nullfd, STDIN_FILENO);
2134         dup2(nullfd, STDOUT_FILENO);
2135         dup2(nullfd, STDERR_FILENO);
2136         close(nullfd);
2137         close(fd2);
2138
2139         for (;;) {
2140                 pfd[0].fd = fd;
2141                 pfd[0].events = POLLIN;
2142                 if ((nfds = poll(pfd, 1, INFTIM)) == -1)
2143                         if (errno != EINTR)
2144                                 error("poll error");
2145
2146                 /*
2147                  * Handle temporary errors, but bail if they persist.
2148                  */
2149                 if (nfds == 0 || !(pfd[0].revents & POLLIN)) {
2150                         if (pfail > POLL_FAILURES)
2151                                 error("poll failed > %d times", POLL_FAILURES);
2152                         sleep(pfail * POLL_FAILURE_WAIT);
2153                         pfail++;
2154                         continue;
2155                 }
2156
2157                 dispatch_imsg(fd);
2158         }
2159 }